This is more subtle that described here. It's a vectorization problem and frankly it should appear on all loop-based string operations and for most compilers (confirmed with gcc, clang and icc). The proposed patch is merely a band-aid ...
More info @ https://bugs.launchpad.net/ubuntu/+source/valgrind/+bug/852760. A better fix for this issue will be to add "-fno-builtin-strdup" to your CFLAGS when compiling Open MPI. George. On Wed, May 21, 2014 at 5:34 PM, Ralph Castain <r...@open-mpi.org> wrote: > Wow, that is hilarious. I see no problem with adding the extra characters :-) > > Scheduled it for 1.8.2 (copied you on ticket) > > > On May 21, 2014, at 3:29 PM, W Spector <w...@earthlink.net> wrote: > >> Hi, >> >> When running under valgrind, I get warnings from each MPI process at >> MPI_Init time. The warnings come from function sec_basic.c at lines 70 and >> 71 (openmpi v1.8.1): >> >> my_cred.credential = strdup("12345"); >> my_cred.size = strlen(my_cred.credential)+1; // include the NULL >> >> This is because strdup(3c) and strlen(3c) are apparently optimized to use >> 4-byte integer loads to speed up the copy and search operations, and >> "overrun" the malloced area. (In fact, since malloc tends to pad >> allocations, it is safe. But valgrind doesn't know that.) >> >> Since the "12345" appears to be a dummy string, would it be ok to add a >> couple of additional characters in the strdup call to: >> >> my_cred.credential = strdup("1234567"); >> >> This gives an 8 byte string (counting the NULL) and quiets valgrind down. >> >> Walter >> _______________________________________________ >> users mailing list >> us...@open-mpi.org >> http://www.open-mpi.org/mailman/listinfo.cgi/users > > _______________________________________________ > users mailing list > us...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/users
